Class: DockerToolkit::Watcher

Inherits:
Object
  • Object
show all
Defined in:
lib/docker_toolkit/watcher.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Watcher

Returns a new instance of Watcher.



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# File 'lib/docker_toolkit/watcher.rb', line 9

def initialize
@lock = Mutex.new

@procs = []
@code = 0
@crashed = false
@threads = []
@who = nil
@stopping = false
end

Instance Method Details

#add(*cmd) ⇒ Object 



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# File 'lib/docker_toolkit/watcher.rb', line 77

def add(*cmd)
  cmd = cmd.flatten.map{|c| c.to_s.strip}.reject(&:empty?)
  process = ChildProcess.build(*cmd)

  rerr, werr = IO.pipe
  rout, wout = IO.pipe

  process.io.stdout = wout
  process.io.stderr = werr
  process.duplex = true

  meta = {
    cmd: cmd,
    process: process,
    stdout: rout,
    stderr: rerr,
    stdin: process.io.stdin
  }

  @threads << Thread.new(meta[:stdout], STDOUT) do |io, out|
    loop do
      break unless synchro_readline(io, out)
    end
  end

  @threads << Thread.new(meta[:stderr], STDERR) do |io, out|
    loop do
      break unless synchro_readline(io, out)
    end
  end

  log "Starting #{meta[:cmd]}"
  meta[:pid] = meta[:process].start.pid

  @procs.push(meta)
  meta
end

#error(msg) ⇒ Object 



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# File 'lib/docker_toolkit/watcher.rb', line 127

def error(msg)
  STDERR.puts "[watcher]: Error: #{msg}"
end

#exec ⇒ Object 



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# File 'lib/docker_toolkit/watcher.rb', line 131

def exec
  %w[EXIT QUIT].each do |sig|
    trap(sig) do
      stop_all
    end
  end


  %w[INT TERM].each do |sig|
    trap(sig) do
      log "Catch #{sig}: try exits gracefully.."
      stop_all
    end
  end

  trap('CLD') do |*_args|
    unhandled = @procs.reject do |meta|
      meta[:handled] || !meta[:process].exited?
    end

    unhandled.any? do |meta|
      log 'Child finished'
      log "  Process[#{meta[:pid]}]: #{meta[:cmd]}"
      log "    status: #{meta[:process].crashed? ? 'crashed' : 'exited'}"
      log "    code:   #{meta[:process].exit_code}"

      meta[:handled] = true
      begin
        meta[:stdin].close
      rescue StandardError
        nil
      end
      begin
        meta[:stdout].close
      rescue StandardError
        nil
      end
      begin
        meta[:stderr].close
      rescue StandardError
        nil
      end

      if !@crashed && meta[:process].crashed?
        @crashed = true
        @code = meta[:process].exit_code
        @who = meta[:cmd]
      end

      unless @stopping
        log 'Try exits gracefully..'
        stop_all
      end

      true
    end
  end

  begin
    yield(self)
  rescue StandardError => e
    @crashed = true
    @code = 1
    error e.inspect
    error e.backtrace.last(20).join("\n")
    log 'Try exits gracefully..'
    stop_all
  end

  @threads.map(&:join)

  @code = [@code || 0, 1].max if @crashed

  exit(@code || 0)
end

#log(msg) ⇒ Object 



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# File 'lib/docker_toolkit/watcher.rb', line 123

def log(msg)
  puts "[watcher]: #{msg}"
end

#stop_all ⇒ Object 



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# File 'lib/docker_toolkit/watcher.rb', line 20

def stop_all
      @stopping = true

      terminating = @procs.reject do |meta|
meta[:handled] || meta[:process].exited?
      end

      terminating.each do |meta|
begin
  meta[:stdin].close
rescue StandardError
  nil
end
::Process.kill 'TERM', meta[:process].pid
      end

      terminating.each do |meta|
begin
  meta[:process].poll_for_exit(5)
rescue ChildProcess::TimeoutError
  meta[:process].stop(1)
  meta[:stdout].close
  meta[:stderr].close
end
      end

      unless @crashed
meta = @procs.detect do |meta|
  meta[:process].crashed?
end

if meta
  @crashed = true
  @code = meta[:process].exit_code
  @who = meta[:cmd]
end
      end

      @procs.each do |meta|
begin
meta[:stdout].close
      rescue StandardError
nil
      end
begin
meta[:stderr].close
      rescue StandardError
nil
      end
      end

      Thread.new do
sleep 2
@threads.each(&:terminate)
      end
end

#synchro_readline(io, out) ⇒ Object 



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# File 'lib/docker_toolkit/watcher.rb', line 115

def synchro_readline(io, out)
  str = io.gets
  @lock.synchronize{ out.puts str }
  true
rescue StandardError => e
  false
end